To enhance the welding strength with a small current value and reduce the dispersion in a parallel type resistance welding with a lead material by forming a plating layer consisting of an Ni-based alloy partially or entirely on the outside surface.
A plating layer of Ni-based alloy is formed by means of electric plating so as to cover the whole surface of a base material of battery can or the part for welding a lead material thereof. The plating layer is preferably formed of an alloy of Ni; Fe, Co, Zn or Fe; and Co in prescribed ratios, which consists of a single phase in which these elements are dissolved in the crystal lattice of Ni or the combination of a plurality of phases. Since the specific resistance is larger than a single body of Ni or other elements, a stable nugget can be formed even with a small current value in a parallel type resistance welding. The alloy with Fe the content of which is set to 50 atom % or less in order to prevent rusting is particularly preferable. The thickness of the plating layer is suitably set to 5 μm or less, or 4.5 μm or less in case of Ni-Fe alloy, and the dispersion in welding strength can be suppressed.
MATSUI TSUTOMU
KITATSUME HIDEAKI
SHIMIZU NORIYUKI
NISHIKAWA REIJI
